Change the name of the `IsInt` property to reflect that it is only doing a type comparison.
Make the `IsOfTypeInt` property internal, as it should only be used by the library implementation.
Create a public `IsInt` property that consumers can use to check whether `AsInt` is valid.
If the wrapped object is an int, naturally IsInt should return true without having to convert it to a string and back.
If wrapped object is null, IsInt should return false.
Write ValueObject unit tests.
Make ValueObject constructors internal, as consumers have no business instantiating them.
Make incrementing method internal since consumers have no business mutating these objects.
Merge pull request #6 from kyle-fritz-zocdoc/InternalsRefactoring

Make `ValueObject.IsInt` reflect the object's ability to convert to integer